This application represents the first application from the Boston Pediatric AIDS CLINICAL TRIALS UNIT (ACTU), a new entity which has grown out of collaboration between the pediatric ACTUs located at Children's Hospital (CH) and Boston City Hospital (BCH). A single program is proposed which will capture the unique advantages of the Boston Children's Hospital's large referral network in Massachusetts and other New England states, and the Boston City Hospital's commitment to the inner city residents who have a disproportionate risk of infection. The number of HIV-infected patients, the spectrum of protocols available, and the diversity of key personnel complements the already well-established outreach to and identification of HIV-infected women, infants and children, and the successful programs for longitudinal follow-up of patients enrolled on AIDS Clinical Trials Group (ACTG) protocols. The Specific Aims and Long-term Objectives of this proposal are to offer a single, multidisciplinary, community-sensitive unit, based in the two institutions who together see almost all the HIV-infected children in Boston and the majority of those in Massachusetts, along with the three obstetrical units which serve most of the known HIV-positive women in Eastern Massachusetts. The unit will bring pediatric and perinatal treatment and prevention protocols into the reach of the largest number of HIV-infected families possible and will offer optimal convenience to patients and their families. The application includes plans for following existing women and children on ACTG protocols as well as adding 50 new patients per year for four years. Perinatal protocols will be conducted at BCH, the Brigham and Women's Hospital and the Beth Israel Hospital (BIH), making use of referral networks established in previous natural history studies. Women on perinatal protocols will be rolled over into adult ACTG protocols at the BCH and BIH. The laboratory support for this program is in the form of the existing HIV laboratory at Children's Hospital, lmmunology Laboratories at both CH and BCH, and a Pharmacology Laboratory at BCH. Included in the application are two developmental studies: one in the virology and immunology of vertical transmission of HIV, virologic studies of drug resistance, and a protocol to study neurodevelopment of infants and children in relation to family care environment and support patterns.